main.dart
void main() => runApp(DemoApp()); class DemoApp extends StatelessWidget { const DemoApp(); @override Widget build(BuildContext context) { return ChangeNotifierProvider<DownloadProgress>( create: (_) => DownloadProgress(), child: MaterialApp( home: Scaffold( appBar: AppBar( title: const Text("Download Demo"), ), body: Center( child: const DownloadWidget(), ) ) ), ); } }
progress.dart
class DownloadProgress with ChangeNotifier { double get progress => _progress; void start({ required String url, required String localPath}) async { // Reset in case it isn't at zero _resetProgress(); // Path and name final directory = await getTemporaryDirectory(); final fileName = "${directory.path}/$localPath"; // Donwload the file await Dio().download(url, fileName, options: Options( headers: { HttpHeaders.acceptEncodingHeader: "*" } ), onReceiveProgress: (received, total) { if (total != -1) { var pos = received / total * 100; _updateProgress(pos); } } ); } double _progress = 0; void _resetProgress() { if (progress != 0) { _progress = 0; notifyListeners(); } } void _updateProgress(double value) { _progress = value; notifyListeners(); } }
download_widget.dart
class DownloadWidget extends StatelessWidget { final String url = "https://website.com/files/something.pdf"; const DownloadWidget(); @override Widget build(BuildContext context) { return Center( child: Consumer<DownloadProgress>( builder: (context, status, _) { var progress = status.progress.toStringAsFixed(1); return RaisedButton( child: Text("$progress %"), onPressed: () => status.start(url: url, localPath: "file_p2.pdf" ), ); }, ), ); } }
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